Gauge for measuring internal dimensions



1957 D. s. STALHANDSKE ETAL 2,781,585

GAUGE FORMEASURING INTERNAL DIMENSIONS Original Filed Feb. 17, 1949 3Sheets-Sheet 1 Hg. 1 a f, i j 5;, Ha I /4/- I70 l68| I69 1i 1, w

Feb. 19, 1957 D. s. STALHANDSKE ETAL 2,781,535

GAUGE FOR MEASURING INTERNAL DIMENSIONS Original Filed Feb. 17. 1949 5Sheets-Sheet 2 v2 m9 RE gvwmboto ble Jim/w.

8 I QW Feb. 19, 1957 0. G. STALHANDSKE ETAL 2,781,585

GAUGE FOR MEASURING INTERNAL DIMENSI ONS Original Filed Feb. 17, 1949 3Sheets-Sheet 5 mam 62 4 0 A uh n2 2 o E 8w am mm m 3 8m 2w 2% g a 2GAUGE FOR MEASURING INTERNAL DIMENSIONS David Gabriel Stalhandske andErik Arne Johnson, Bofors, Sweden 10 Claims. (Cl. 33-174) The presentinvention relates to gauges for measuring the dimensions of finishedwork pieces and is a division of our co-pending application Serial No.76,894, filed February' 17, 1949, now Patent No. 2,692,045, issued Oct.19, 1954, relating to a machine for automatically gauging and sortingwork pieces.

With machines of the above type it is often necessary to gauge one ormore internal dimensions in a work piece such as the depth or diameterof a bore, female threading, groove depth and width, etc. The novelinternal or plug gauge structure to be hereinafter described is adaptedto measure a plurality of such dimensions simultaneously and the severaldimensions gauged are converted respectively into correspondingdisplacements of the movable element of an electrical contactor device,the latter serving to condition an electrical circuit which controls asorting device at the sorting station when any work piece whosedimensions exceed the selected tolerance arrives there. The sortingstation is more particularly described in our aforesaid co-pendingapplication.

With reference now to the accompanying drawings which present apreferred embodiment of the invention:

Fig. 1 is a view in vertical longitudinal section showing the gaugemounting and the electrical contactor device in position for gauging;

'Fig. 2 is a view in vertical transverse section on line 2-2 of Fig. 1;

Fig. 3 is a view similar to Fig. 1 illustrating a modified constructionfor mounting the gauging elements in relation to the contactor device;

Fig. 4 is a view in vertical longitudinal section on line 44 of Fig. 5of one form of the multiple element internal or plug gauge;

Figs. 5 and 6 are vertical transverse sections on lines 5-5 and 6-6 ofFig. 4, respectively;

Fig. 7 is a view similar to Fig. 4 on line 77 of Fig. 8 showing amodified construction for the gauging elements;

Fig. 8 is an end view of the gauge in Fig. 7;

Fig. 9 is a view in vertical longitudinal section on line 9-9 of Fig. 10showing a further modification of the plug gauge particularly adaptedfor gauging female threadin Fig. 10 is a view in vertical transversesection on line 1010 of Fig. 9;

Fig. 11 is a view in vertical longitudinal section of still anotherembodiment of the novel plug gauge and which is particularly adapted forgauging internal grooves;

Figs. 12 and 13 are details of the gauge in Fig. 11;

Fig. 14 is a diagrammatic view used in explanation of certain featuresof the invention; and

Fig. 15 is a view of the electrical contactor device used with eachgauging element with the cover removed to show its structural detail.

With reference now to the drawings and in particular to Fig. 1, thegauge is seen to be comprised of a support base 161 that is adapted tobe reciprocated horizontally to and from the work piece to be gaugedwhen the Work United States Patent 0 2,781,585 Patented Feb. 19, 1957piece arrives at the measuring station as more particularly Car--described in our aforesaid co-pending application. ried upon support 161is a primary piston 162. One end 163 of the piston is connected with anarm 61 which transmits a so-called secondary movement to piston 162'after the gauge support 161 has been given its primary movement in thedirection of the work piece.

Within piston 162 are smaller secondary pistons 164 (six in number)distributed over an arc of substantially 180, the pistons 164 beingjournalled in horizontal bores in the larger piston 162 for displacementin a direction along their respective axes. At the right end of thesupport base 161 an upstanding portion is provided which contains anaperture 165 for receiving a gauging element casing containing aplurality of concentrically arranged, independently slidable pressuresleeves 167 by which movement is imparted to the several gauge elementstobe later described.

The center of aperture 165 is offset from that of piston 162 so that thepistons 164 can be positioned helically relative to the center ofaperture 165 thus enabling the circumferentially spaced shoulders 166 onthe sleeves 167, by turning of the gauge, to be brought into engagementwith the front ends of their associated pistons 164, the said front endsbeing made with corresponding recesses the contact surfaces of which lieat right angles to the longitudinal axes of the pistons. Thus the pluggauge may be easily removed and mounted respectively when necessary forreplacement.

The pistons 164 are kept pressed forwardly (to the right as viewed inFig. 1) relative to piston 162 by springs 168, the power of which isselected for the measuring pressure desired for transmission via thesleeves 167 to the gauging elements as piston 162 is pushed forwardlywhen the measurements are made, but each piston 164 stops in theposition corresponding to the particular dimension of the work piece forthe respective place of measuring when the gauging element associatedwith that particular piston is stopped by the surface of the work piece.Check nuts 169 which strike against piston 162 are provided on the leftends of pistons 164 to limit return movement of pistons 164 by springs168 when the piston 162 returns to its starting position.

Each piston 164 is provided with a notch 170 that establishes a shoulderfor engagement with the actuating lever 143 of an electrical contactordevice 141 which is fixed to the support base 161.

The contactor device as best shown in Fig. 15 is adapted to close anelectrical circuit when the dimension in question exceeds the maximum oris less than the minimum limit of tolerance chosen. It is comprised ofthe casing 141 housing a pair of stationary, spaced contact members 148,149 each held against an adjustment screw 147, that threads through thewall of casing 141, by means of a cantilever spring 150, and a pivotallymounted contact arm 145 having a contact 146 at its outer end adapted tomove in an arcuate path between the stationary contacts 148, 149. Aspring 151 loads arm 145 in the direction of contact 148. For actuatingarm 145, a pivoted lever 142 is utilized. The upper end 144 of lever 142bears against arm 145 and the lower end 143 protrudes from casing 141.Lever 142 also is loaded by a spring 152 so that the upper end 144 willalways bear against arm 145 in such manner as to load the latter in thedirection of stationary contact 149. The relationship between the twoloading spring forces derived from spring 151 (acting directly upon arm145) and spring 152 (acting directly upon lever 142) is so chosen thatthe latter will predominate with the result that in the rest position asshown in Fig. 15 contact 146 on arm will be pressed against stationarycontact 149. As lever 142 is caused to turn counter-clockwise however bymovement of piston.

3 164, springlSl is then free to exert its-force upon a'rm 145 causingthe latter to follow and maintain contact with the upper end 144 oflever 142.

Before a work piece with'axia'hboresto be gauged arrives at themeasuring-station, the base support 161 carrying the gauge structureoccupies aposition far enough to the left as viewed in Fig. 1 to provideclearance between the'cnd face of the work piece and the outer or rightend of the gauge structure. When 'the work piece has arrived and comesto a stop at the measuring station, the base support 161 then slides tothe right to a predetermined initial 'or zero position from which themeasurements are taken. In this position the gauging elements will beinside of thebore in'the work piece. Piston 162 is then slid to theright by arm 61 causing like movement of pistons 164 which through thesprings 168 exert end pressure upon and displace the sleeves 167 to theright. Each sleeve 167 and the gauging element associated therewith willthen travel until the gauging element comes to a stop against theparticular surface in the base of the work piece assigned formeasurement. After measurement has been taken arm 61 draws piston 162 tothe left to the initial position and the pistons 164 follow the movementof pistion 162 due to the engagement between the end of piston 162 andthe check nuts 169 on pistons 164. The base support 161 also shifts tothe left removing the sleeves 167 and gauging elements from the bore ofthe work piece so that the latter can pass on to the next measuringstation for gauging other dimensions of the bore.

In the case of a plug gauge of the construction shown in Fig. 7, to belater described in more detail, and which is equipped with gaugingelements corresponding to minimum dimensions of the bore in the workpiece which the respective element shall be able to enter when havingthe accepted dimension but cannot enter if the bore is smaller than thisminimum dimension, the gauging element and the pressure transmittersleeve acting upon the same must be allowed'a recoiling movementrelatively to the measuring device, corresponding to the length of thebore, in order that the whole measuring device shall not be forced tostop when his about to advance to measuring position. If the recoilingmovement needed is larger than that permitted by the mounting shown inFig. l, the piston 162 with its associated components, pistons 164,springs 168, etc. is removed and the base 161 only is used as a mountingin the manner shown in Fig. 3. There it will be observed that theshoulders 166 of the pressure transmitting sleeves 167 bear 'directlyupon the arms 143 of the electrical contactor devices when in measuringposition but are separated'from the arm in case of recoil'movement tothe left. The necessary measuring pressure on each pressure transmittingsleeve of Fig. 7 mounted as in .Fig. 3 is suitably obtained by means ofsprings 187 inserted in the body of the plug gauge, as shown in Fig. 7which load the sleeves towards the right.

The gauging element of the plug gauge which during the measurement ispushed into the bore of the work piece containing the surfaces to begauged must be suited to the particular character of that surface.Different measuring methods for different measures may be combined inOne plug gauge; at the same time as certain measurements of a certainsurface (for instance, cylinder or thread) may be effected in one pluggaugeand the other in one of several other plug gauges mounted atdifferent measuring stations to which the work piece is brought.

Figs. 4, 7, 9 and 11 show by way of example different arrangements ofgauges wherein different methods of measurement are provided to meetdifferent require ments. V

In Fig. 4, the gauge is characterized byte cylindrical casing 1'76havinga tubular portion 177 thereof of re duced "diameter to-bereceivedin theaperture of'the slidable base 161. Mounted within the tubular portion177 are a plurality of measuring elements 178-183 actuatablerespectively by axially slidable concentrically arranged pressuresleeves 184 and rod 185 the ends of which protrude beyond the end of thetubular portion 177, and are provided with helicoidally positionedshoulders 186, as best viewed "in Fig. 6, for engagement with actuatingelements therefor such as the pistons 164 in Fig. 1. It will berecognized that the sleeves 167 and projections 166 of Fig. 1 are thesame functionally speaking as sleeves 184'and projections 186 of Fig. 4.

A further feature of the gauges is the arrangement of the differentmeasuring elements 178183 in such manner as to obtain a certain degreeof floating without affecting the measurement, i. e. that themeasurement is not made dependent upon an exact centering between thegauge and work piece, 'and that when measuring depths anddiameters ofbores with so-called fixed measuring bodies, these are adapted to engagestop shoulders 188, see Figs. 8 and 12, lying in the same horizontalplane, which establish a horizontal substantially line contact thatpermits a certain inclination of the work piece with respect to thisplane without affecting the degree of accuracy of the measurements. Thisfeature is of importance where the work piece is placed in V-shapedblocks for measurement and outside diameters thereof at the V blocksdeviate differently from the normal diameter but are still within theselected range of tolerance of manufacture which of course gives rise tothe inclination under consideration. Thus with reference to Fig. 14 itis apparent that for a small angle on of work piece inclination fromhorizontal, the distance A1 becomes practically equal to distance A2,which is the case when stop shoulders 188 are used, whereas distance BWill be greater than distance A1 if the stop shoulders 188 are omitted.

With reference now to Fig. 4 in particular, the plug gauge thereillustrated is capable of performing six difterent measurements withinthe body of the work piece P. The diameter of the internal bore a isgauged with the centermost measuring element 178 at the end of rod 185.The outer shell of element 178 can consist of either two cylindricalparts, each one at the front provided with a bevel (and a clearancegroove intermediate the cylindrical parts where deeper bores are to bemeasured) or of two spherical parts, or a combination of cylindrical andspherical parts as illustrated, the front part in both casescorresponding to the maximum diameter of the bore so that when themeasuring element is pushed axially into the bore a, the front part willgo in but not the rear one if the bore diameter is within the selectedlimit of tolerance. If the bore is smaller than the minimum limit of thetolerance range, the fore part will not go in, and if it exceeds themaximum limit. the rear part also will pass into the bore. The axialaperture through the measuring element 178 is of somewhat largerdiameter than that of the end portion of rod 185 on which it is mountedto provide a certain amount of radial clearance or play 189 therebetweenwhereby the necessary floating, as previously discussed. is obtained.

In the work piece P, the bore b adjacent bore a is of largerdiameterthanbore (z with sharp line of do marcation therebetwecn. Consequentlysince bore 0 is not a through bore a gauging element of the taximunuminimum type such as gauge 178 cannot be used, and the maximum andminimum limits must be measured separately at different measuringstations and with dif ferent gauges. The maximum diameter of the bore bcan be gauged with the measuring element 179 of the plug gauge of :Fig.4. The outer shell of gauge element 179 can consist of a sphericalsurface or as illustrated a cylindrical surface ;providcd with anentering :bevel at the front end. The outer diameter of element 179corresponds to the maximum diameter of bore 11 for which reasonelem-ent179 will be stopped if the diameter of bore b is within therange of tolerance, in which case the said gauge element will reach theouter edge of bore [2 upon movement of the measuring element 179 butpasses into bore b if the diameter exceeds the tolerance limit. Element179 is actuated by one of the sleeves 184 and radial clearance 189 isprovided for in its mounting to permit a floating action.

With respect to the next adjacent bore 0 in the work piece P- which isof still larger diameter, the gauge element for measuring its maximumdiameter is comprised of a cylindrical portion of the gauge body 176provided with three equally spaced .radially extending bores containinggauging balls 180. A sleeve 197 of springy material partially covers theouter ends of the bores to prevent the balls from dropping out, and theballs are moved radially to gauge the bore c by means of a cone 196movable axially by one of the sleeves 184, it being noted that radialplay is also provided for floating of the conical body 196 as in thecases of the two other measuring elements 178 and 179.

-The gauge structure of Fig. 4 also includes a gauging element formeasuring the inner diameter of a female threaded portion of work pieceP, i. e. the diameter at the tops of the threads. For this purpose,radially movable pistons 181 are utilized, the outer ends of the pistonsengageable with the tops of the threads being cylindrical in shape whilethe inner ends engageable with the axially displaceable conical body 196are inclined to match the taper on cone 196. Pistons 181, at least threein number and equally spaced'about the axis of the gauge are slidable inbores disposed in the tubular gauge casing 176 and are prevented fromfalling out by a ring 193 of springy material guided radially in agroove around the outer surface of casing 176, the ring 198 restingagainst a recess located in the outer ends of pistons 181 and pressingthe pistons inwardly when the associated pressure sleeve 184 shifts tothe left after the gauging operation.

Also included in the Fig. 4 gauge structure are means for measuring thediameter of a bore d at the end of work piece P and the diameter of aconical portion of the exterior surface at the end of the work piece.For

'measuring the diameter of bore d, a plurality of fingers 182 serve asthe gauging elements. The outer free ends of these fingers are adaptedto be moved radially outward by pistonsZtltl slidably mounted in radialbores in the gauge body 176 by another cone 196 as the latter is slid tothe right by its associated pressure transmitting sleeve 184 and theopposite ends of fingers 182 are attached to the gauge body 176. Thefingers 182 have an inherent resilient characteristic which causes theirouter ends and also pistons 200 to move radially inward as cone 196 ismoved to the left after measurement has been taken.

For measuring the diameter of the cone surface, a

plurality of levers 183 pivotally mounted intermediate their ends uponthe gauge body 176 are utilized. The lever ends adjacent the surface tobe measured are adapted to move radially inward to engage the conesurface as their opposite ends are pushed radially outward by pistons200 also slidable in radial bores in gauge body 176 by'another of thecones 196 and its associated sleeve For measuring the minimum limit of abore having asharp demarcation indiameter such as bore 1) in the workpiece, a cylindrical measuring element 1% as illustrated in the pluggauge construction of Fig. 7 must be utilized. The diameter of themeasuring element 190 corresponds to the minimum diameter of bore 1) andat the front or leading end the element is provided with an enteringbevel 194 which is largest on the lower side and decreases upwards sothat the upper side will correspond. to the exact curvature of the boreb. The measur ing element 190 is attached to the end of rod 185 in suchmanner as to provide radial play 189 therebetween therebygiving theelement a floating action. A set screw 195 is used to'lock the element190 upon rod to prevent 'relative rotation therebetween. Rod 185 is alsoprovided with a longitudinally extending flat 225 in contact With theend face of a pin 226 anchored in the Wall of the cylindrical portion177 of the gauge body which permits rod 185 to move along its axis butprevents its rotation about its axis. Because the element on account ofthe radial play space 189 prior to be-' ing pushed into the interior ofthe work piece and bore b in particular may be located somewhat lowerthan bore 11, it is evident that the entering bevel 194 will be usefulunder such conditions to guide the element into the bore.

The gauge construction of Fig. 7 also includes a somewhat differentgauge element for measuring a bore 0 such as includes a bevelled outeredge and rounded inner end. Here the gauging element is in the form of acylindrical cup 191. The base of the cup 191 is apertured 'for mountingupon the end of its associated actuating sleeve 184 in such manner as toestablish a certain amount of radial play space 189, and the edge of thecup is shaped to conform with the rounded inner end of bore 0. With thisconstruction it is thus not necessary to provide the gauging elementwith any special entering bevel such as bevel 194 of gauge element 190since the rounded cup edge in combination with the fioating" action ofthe cup are all that are necessary to assure entrance of the gaugeelement in the bore.

In the measuring methods which have been described, the tolerance limitsof the several different bore minimum diameters of work piece P aredetermined through the outer diameter of the respective measuringelement, for which reason the tolerances registered on themaximumminimum indicators 141 will be the tolerances on the depthdimension of the bore and not the diameter tolerances, and therefore thediameters as well as the depth of the bores are gauged simultaneously.In the event the bore is not too deep and the diameter is less than theminimum limit of tolerance, the minimum gauge element will not pass intothe bore, and as a consequence the work piece will be sorted out at thesorting station as a correctable one. However if the bore is too deep,the work piece should be sorted out as uncorrectable.

If it is desirable to prevent such events, measurement of the bore depthmay be effected separately with a gauging element having a diameter asmuch below the minimum tolerance limit as may reasonably be anticipated.Thus in Fig. 7 the cup-shaped gauging element 193 for measuring thedepth of bore section d separately is connected at its base with itsassociated sleeve 184, the connection being rigid, that is withoutradial play. The diameter of the cup 193 is obviously much less than theminimum tolerance limit for bore a and to assure entry in the event theWork piece is slightly inclined from horizontal, the front side of thecup 193 is provided with shoulders 188 disposed in a horizontal plane asshown in Fig. 8.

Measurement of conical surfaces on the work piece may be carried outaccording to the Fig. 7 construction by a gauge element in the form of acup 192 secured at its base to the associated sleeve 184 in such manneras to permit radial play therebetween. The edge of the cup is taperedtomatch the taper on the conical portion of the work piece, themeasurement taking place at a fixed distance from the basic plane of thecone or from another plane at a right angle to the longitudinal axis ofthe cone, depending upon the dimensions of the work piece.

The gauge construction shown in Fig. 9 is adapted particularly forgauging the mean diameter and profile of female threads in the workpiece. The gauge body 176, 177 is adapted for support upon base 161 inthe manner shown in Fig. l or Fig. 3 and includes at least three equallyspaced threading dies or anvils 2116 which in axial direction aredisplaceably journalled in radially movable pistons 207 actuated by afloating cone 196 and a resilient rings 208 the p'owercof which is ofcourse less than the spring power which 'via the rod 135 and cone 196presses anvils 206 outwards when measurement is taken. Since anvils 206are axially displaceable, the threaded edges thereof can float axially:into the thread to be gauged independently of the axial initialposition of the thread profile for instance through oblique recesses 209located in front of and behind i.'e. on both sides of the anvils, 'therecesses 209 being arranged so as to permit some play between anvil andthread no matter what their initial positions may be.

If the thread to be .gauged'ha's a plane top rather than a sharp 'edge,in which case it is possible that automatic alignment between thread andanvil will not under some conditions take place, the gauge is preferablyprovided with a special mechanism which exerts an initial axial push onthe anvils .206. This mechanism consists for instance of a striking pin210 actingaxially'upon each anvil which pin by means of a ball 211 isactuated by a earn 212 on pressure sleeve 184, the latter being actuatedaxially along with rod 185. When actuating pin 210 to the right, hall211 rides against the face of cam 212 opposite from that shown in Fig.9. Ball 211 is pressed against cam 212 by a spring actuated piston 213so that in cases when anvils 206 slide into the thread withoutcoincidence with the tops of the thread, piston 213 springs back whencam 212 pases ball 211. Piston 213 likewise. springs back for the cam212 when pressure sleeve 184, after the measuring operation, iswithdrawn to its initial position. Should the anvils'206 and pistons 207fail to return to their radially inward position damage to the gauge maybe the result when it is withdrawn from the work piece. To avoid thisrisk, pistons 207 are journallcd in a body 214- which by means ofsprings 215 is kept pressed against and guided by the gauge body 176.Springs 215 and body 214 are adapted to cooperate in such a manner thatshould body 214 as well as pistons 207 and anvils 206 jam in the workpiece they will separate without damage from the rest of the gaugestructure when the latter is withdrawn from the work piece. Theseparated pieces can then be reunited by pressing the same together.

216 corresponding to the minimum width of the groove and protruding intothe groove, are displaceably journalled in axial direction in radiallymovable pistons 207 which are actuated by a floating cone 196 andpressure transmitter rod 185. Pistons 207 are pressed radially inward bya split resilient ring 208 and the cone 196 pushes the pistons 207 andanvils radially outward against the counter radial force of ring 208.The anvils 206 are from one end actuatable axially by a pressuretransmitter sleeve'184 with the aid of pistons 217 and two plates 218,219 disposed between pistons 217 and the flanged end of sleeve 184.Plate 218 adjacent the flange of sleeve 184 is provided with diametralribs 183 on its opposite faces, the rib on one face being perpendicularto that on the opposite face as shown in Fig. 13 whereby to eliminateany influence on the measurement of groove depth as may be caused bypossible inclination of the work piece and exactness of manufacture ofthe length dimensions of pistons 207 and anvils see. From the oppositedirection anvils 206 are actuated axially by a spring 220 less powerfulthan the force actuating sleeve 184 in the pposite direction.Consequently at the time of taking a measurement anviis 206 will bedisplaced axially until they arrive right in front of the groove atwhich moment they are pressed out by cone 196, and after the measuringis-finished, the anvils 206 return to their initial positions. the depthdimension measured in the present example egins at the bottom of thebore, and therefore the stop shoulders-188 of the gauge are disposed atthe end surface of the gauge.

If the anvils 206 and pistons-207 should fail to return to their initialpositionsafter measurement'has been taken the plug gauge would jam andfor that reason is'made divisible like the gauge shown in Fig. 9 andtherefore includes the same corresponding elements, namely body 214 andthree springs 215.

In conclusion we desire it to be understood that while the constructionof each embodiment of our inventionas described above is preferred,various minor changes in the construction and arrangement of componentparts may be made without however departing from the spirit and scope ofthe invention as defined in the appended claims.

We claim:

1. A gauge device for measuring simultaneously a plurality of internaldimensions of a work piece comprising a plurality of pressure membersstepped in length arranged coaxially each within the other for slidinglongitudinal displacement between fixed limiting positions, gaugeelements individual to and actuated by one end of each said pressuremember for gauging different dimensions of said work piece, thedisplacement of each said pressure member being a measure of thecorresponding dimension to be measured, each saidpressure member beingprovided at its opposite end with a shoulder and said shoulders beingarranged in circumferentially spaced relation, spring means formaintaining each of said pressure members at one of its limitingpositions and gauge indicating means individual to each said pressuremember, each said guage indicating means being arranged incircumferential alignment with said shoulder on the respectivelyassociated pressure member and being actuated by means including saidshoulder.

2. A gauge as defined in claim 1 and wherein said pressure members aretubular of circular cross-section and each is slidable along the surfaceof the other.

3. A gauge of the type defined in claim 1 for measuring a bore in thework piece and wherein one of said gauging elements is comprised of twoaxial sections each provided with an entering bevel at the leading end,the front sec- -tion corresponding to the minimum of the range indiametral tolerance selected for said bore and the rear sectioncorresponding to the maximum of said range in tolerance.

4. A gauge of the type defined in claim 3 wherein said pressure memberassociated with said gauging element having said two axial sections isconstituted by a shaft on which said element is mounted, there being aslight radial clearance between said shaft and gauging element to permita corresponding floating action of said gauging element.

5. A gauge device as defined in claim 1 wherein one of said gaugingelements is comprised of a plurality of radially displaceable elementsactuated by an axially displaceable cone, said cone being mounted on afirst one of said pressure members and with a slight radial clearancetherebetween to permit a corresponding floating action of said cone andsaid cone being engageable by a second one of said pressure memberssurrounding said first pressure member to effect the said axialdisplacement thereof.

6. A gauge of the type defined in claim 1 for measuring internal threadswherein said radially displaceable elements are constituted by pistonshaving cylindrical shaped parts facing the thread, the ends of saidpistons contacting the said cone having the same angle of inclination asthat of said cone, and which further includes means preventing saidpistons from rotating on their axis and means biasing said pistonsradially inward.

7. A gauge of the type defined in claim 1 and which further includes aplurality of radially spaced lever arms pivotally mounted intermediatetheir ends for movement in radial planes, said lever arms being engagedrespectively by said radially displaceable elements.

8. A gauge for measuring internal dimensions of a work piece comprisinga support base, a tubular casing carried by said support, a plurality ofconcentrically arranged pressure members journalled in said casing forsliding movement axially thereof and each having a shoulder portion atone end thereof, said shoulder portions being arranged incircumferentially spaced relation, a gauging element individual to andactuated by the other end of each said pressure member, a primary pistonmounted on and slidable along said base axially of said pressuremembers, a plurality of secondary pistons slidable axially Within saidprimary piston, said secondary pistons being arranged in radially spacedrelation about a central axis for engagement respectively with acorresponding one of said shoulder portions, a spring associated witheach secondary piston for loading the same in the direction of saidshoulder portion associated therewith and an electrical contactor deviceindividual to each secondary piston and including a movable contactactuated thereby.

9. A gauge for measuring internal dimensions as defined in claim 8wherein the said central axis for said secondary pistons is oifset fromthe common center of said concentrically arranged pressure members.

10. A gauge for measuring internal dimensions as delined in claim 8wherein said pressure members are con stituted by shafts on which saidgauging elements are mounted, there being a slight radial clearancebetween said shafts and the respective gauging elements to permit acorresponding floating action of said elements.

References Cited in the file of this patent UNITED STATES PATENTSBarholdy M Aug. 21, 1923

